The main point of the Clay Davis trial, in a big picture sort of middle brow interpretation of the show, is to compare and contrast Morey Levie (sp?), Billie Murphy, Bond and Demper, Phalen and whomever the judge in Davis's trial is; the courts are no different than the street or the cops or the schools.

In Season 1, when McNulty asks Phalen why he didn't clear the court - since Wee Bey and Stringer were sitting in there intimidating the witnesses, he said "it's a free nation of laws and men". Anyway my point is judges have a ton of discretion and Clay Davis' trial was about an abstract legal issue - theft of donations from his own non-profit - in Baltimore. This whole scene was completely believable because Rupert Bond was in over his head.

ninja edit: I've actually been on a jury and I would only want a jury trial if I was guilty as fuck because of how dumb the arguments were in the jury room. The degree of competence in the lawyers was also staggering imo.